Electric meter.



No. 698,640. Patented Apr. 29. I902.

T. DUNCAN. ELECTRIC METER.

= Application filed June 29, 1898.) v

(No Model.) 2 Sheets-Sheel 2.

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UNITED STATES PATENT OFFICE.

THOMAS DUNCAN, OF FORT WAYNE, INDIANA, A SSIGNOR TO THE SIEMENS (KrHALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

ELECTRIC M ETER.

SPECIFICATION forming part of Letters Patent N 0. 698,640, dated April29, 19 02 Application filed June 29. 1898 Serial No. 684,716. (Nomodel.)

To all whom it may concern.-

Be itknown that I, THOMAS DUNCAN, a citizen of the United States,residing at Fort Wayne, in the county of Allen, in the State. 5 ofIndiana, have invented'certain new and useful Improvements in ElectricMeters and I do hereby declare that the following is 'a full, clear, andexact description of the invention, which will enable others skilled inthe art to which it appertains to make and use the.

same, reference being had to the accompanying drawings, which form partof this specification. My present invention relates to improve I5 mentsin induction motor-meters. I

The objects of my invention are to provide a meter of simple andeconomical construction adapted to measure with accuracy the energyconsumed in inductive translating devices, such as arc-lamps and motors,to

provide in an induction motor-meter an im-' proved method of and meansfor securing a .magnetic field in quadrature with the linepressure forthe accurate measurement of inductive loads, and to provide a meteradapted for use upon more than one rate of alternations and also adaptedto record accurately on any and all of the various frequencies met.

with in alternating-current practice. 0 It is well known that thecustomary manner of measuring inductiveloads and obtain-= ing a lag ofninety degrees in the shunt or volt magnetism behind the electromotiveforce. which it represents in alternating-current motor-meters now inuse is by the employment of the resultant magnetic effect of a plu-,

rality of shunt-coils of differing phase, which when combined with themagnetism of a suitable series coil representing the amperes prodncesrotation of the revoluble metallic armature in a well-understood manner.I secure this desired result in my present invention without thenecessity of employing any subsequent increased rate of cutting.

overcome an objectionable defect found in the meters at present inusevia, their inability to adapt themselves to a wide range offrequencies-as, for example, from sixty'to one hundred and fortyperiodswithout requiring a special adjustment for a given periodicity.

To make the speed of the armature in an induction motor-meter constantwith a constant load on different frequencies, some means mustbeprovided by which the changes in periodicity and rate of cutting of thelines of force through the armature must be compensated for by aninverse change in the density of flux before the armature will respondalike to a given wattage for difiering freequencies'that is, if a meteris adjusted for, say, one hundred and forty periods, then by using thesame meter on sixty periods the reduction in the alternations causes areduction in the rate of cutting of the lines of force, which would as aconsequence reduce the inductive eifect upon the armature, therebycausingit to run slower than on the one hundredand forty periods withthe same number of watts; but by increasing the strength of the magneticfield by an amount that will balanceand compensate for the reduction inthe rate of cutting due to a reduced frequency the speed of the armaturewill remain constant for a constant load irrespective of the chaugeintherate of alternations. Again, if the meter should be calibrated forsixty cycles and it is desired to utilize it on one hundred and fortyperiods also the shunt or pressure field-coil must be so organized thatwhen it is subjected to the higher frequency its magnetic field must bereduced automatically in density by an amount that will balance thetendency to increase torque due to the increased rate of alternationsand 0 The demand for such a meter or one that can adapt itself to any ofthe present periodicities met with in modern centrahstation work israpidly increasing on account of the many older stations being equippedwith high-frequency apparatus, and the present additionsbeinglow-frequency apparatus, in order that their business may successfullyinclude the operation of motors. For this reason a number of centralstations are obliged to carry two different classes of inductionmotor-meters, oneelass adjusted for low frequency and the other for highfrequency, which causes much confusion and'annoyance in keeping themseparated. Another practice which exists today is the feeding oflow-frequency currents during the day for power purposes principally,and during the night, when motors are out of service, the high-frequencydynamos are switched upon the same circuits for lightingpurposes,thereby introducing a condition that cannot be met by anyinduction-meter upon the market at the present time. It must also beborne in mind that in addition to overcoming the foregoing obstacles themeter must be able to also measure accurately.

lagging currents with the various frequencies as well as non-lagging ornon-inductive currents. To overcome the foregoing objections byproducing a meter that can be used on any rate of alternation andmeasure both inductive and non-inductive loads is the principal objectof the present invention.

I have experimentally discovered that if a solid tool-steel core beinserted into the pressure or volt field-coil of an induction-meter.

that a uniform speed of the meter-armature can be maintained with auniform load in wattsirrespective of the rate of alternations- 216.,either seven thousand two hundred or sixteen thousand eight hundred,these being the two extremes in use at present. In connection with theforegoing I have also demon-;

strated experimentally that by a proper adjustment of the solidtool-steel core and the convolutions comprising the present or voltfield-coil,the magnetism produced by the current in said coil can becaused to lag behind said current and maintained at a given angle of lagwhether the current be sixty or one hundred and forty periods, therebymaking it possible for my improved meter to measure inductive loadsaccurately on both sixty and one-hundred-and-forty period circuits.

The manner in which the foregoing conditions are maintained is upon theassumption strength or density of its magnetism for the differentperiodicities, enabling it thereby to maintaina constant value for aconstant electromotive force irrespective of the rate of alternations.The maintenance of the magnetic field in quadrature with thelineepressure through theinstrumentality of thesolid steel core withdifferent frequencies and enabling the instrument to accurately measureinductive loads on said different frequencies is also (1 ue, no doubt,tothe varying control by hysteresis and reluctance of the magnetismthrough said core. This latter quality may, for example,be ascribed tothe solid steel core by assuming that with a high-frequency current themagnetism has a given phase relation with said current-say ten degreesbehind itand which we will assume is also ninety degrees behind theline-pressure. Then by passing a low-frequency current through thepressurecoil that magnetizes the said solid steel core the reluctanceand hysteresis of said core are reduced, thereby permitting a greateramount of effective magnetism through it,and by passing more magnetismthrough it the hysteretic eddy currents are increased, therebymaintaining the phase angle of the magnetism of the core at ninetydegrees. The said increase in eddy currents compensates for the decreasein the self-induction of the pressure-circuit which is traversed by thecurrent magnetizing said solid steel core by increasing the magnitude orvalue of the eddy currents to balance the decrease in self-induction ofthe pressure-circuit, so that on any frequency the effective magnetismthrough the solid core will be ninety degrees or the resultant of the'hysteretic eddies in said core and the magnetism imparted to it by thecurrent traversing the volt field-coil surrounding it.

I am aware that a solid magnetizable core has heretofore been employedfor the purpose of retarding the phase of the magnetism passing throughit; but in no instance of whichI am aware has it been employed tofurther augment the magnetism produced by a previously-lagged current,as set forth and illustrated by my present invention, and which involvesthe lagging of a magnetic field to ninety degrees behind the line-pressure which it represents. Neither am I aware of any application in which asolid steel core is employed in the shunt or pressure field-coil of aninduction motor-meter to accomplish the other results hereinbefore setforthviz., to maintain the magnetism through it at a definite lag-angleirrespective of the periodicity of the system, and making it possibletherebyto measure inductive loads on a circuit supplied by currents ofdifferent periodicities.

My invention comprises as its principal operative parts or elements aseries field-coil, a shuntfield-coil, an impedance-coil, a solidmagnetic core, a revoluble armature in inductive relation to said coils,a registering mechanism, and a damping or retarding device.

In the accompanying drawings, illustrative of my invention, in whichsimilar referencenumerals indicate like parts throughout, Figure 1 is afront elevation showing the relative arrangement of the operative partsof my improvement. Fig. 2 is a plan View of Fi '22 in a well-understoodmanner.

is showna modified form and arrangement of the said lagging core 10,being Ushaped, as

1. Fig. 3' is a front elevation showing the en erg'izing-coilsinverticalsection. Fig.4 is

also a front elevation showing a modified arrangementof'thcshunt-coilsand lagging core, 1

theenergizing-coils beingshown in section. Upon a vertical step 19 iserected the upright revolublearmature-spindle 12, having properbearings'at its extremities and provid-ed uponits upper end with a worm14,

adapted to mesh with and actuate a gearwheel'15 ofaproperregistering-train 16. At

a suitable point on said spindle is rigidly fixed a metallicdisk-armature 11, having the energizing-coil arranged upon oppositesides thereof, the series or ampere-"coil5 upon one side, and the shuntor voltcoils 9 upon the Near the lower end of said spindle is rigidlyfixed a metallic disk 13, which is arranged in inductive relation to theretardother side.

ing-magnet 17, Figs. 1 and 3. A solid magnetic lagging core 10 isadjustably mounted within the shunt-coil 9, Figs. 1, 2, and 3, and inconcentric relation therewith and may be secured in position by a properclamp 20, fixed to a suitable support with the screws 21 and is adaptedfor alongitudinaladjustment with in said shunt-coil by means of theset-screw In Fig. 4

shown, and adapted to have itsends adjustably arranged within a pair ofshunt-coils 9, as shown.

25. Inthese slots are arranged the screws 24,

having their inner end inserted into any proper support, as the back ofthe meter,and

adapted by means of said slots to afford a limited vertical adjustmentof said plate and.

core for the purposehereinafter described. The manner of mounting andadjusting the said lagging core is obviously amere mechanical detail andmay readily be varied at pleasure.

While I have shown the series field as comprising a single coil, aplurality of series coils may be employed, if desired.

The operation of my improvement thus described may be briefly statedasfollows: Itoferring now particularly to Fig. 3, the main current fromthe generator supplying the lamps or translating devices 4, by'means ofthe circuit-leads 2 and3, traverses the series or ampere coils 5, andthereby sets up or establishes a magnetic field whose intensity. isproportional to the current strength. To produce rotation of the saidclosed revoluble disk armature, the following conditions are requisite.The axis of the shunt-coil 9 must be eccentric to the axis of the seriescoil 5 and parallel therewith. The current in the said shunt-coil 9,which represents the electromotive force of the service-mains, must lagbehind the said electromotive force, and since my improved meter isdesigned to measurethe energy on circuits having lagging currents Thiscore 10 is rigidly connected to the horizontal bar or plate 23, havingits opposite ends providedwith a transverse slot the magnetism throughthe said shunt-coil 9 must lag ninety degrees behindthe pressure I ofthe system and must also be in quadrature secure a quadratureofthemagnetism of the said shunt-coil with the line-pressure, which isthe principal object of my invention, I introduce an impedance-coil 8 inseries with the said shunt-coil 9; thereby producing a lagof the currentthrough'thiscircuit necessarily somewhat less than ninety degrees.To'secure the required lag of said current or ninety degrees, I arrangethe said solid magnetic core 10 Within the said shunt-coil, andby thusutilizing the hysteretic and reluctive qualities of said core I securethe desired result. The magnetism of the said core 10 can readilybeadjusted to exact quadrature in either one of twowaysby varying thecurrent through the saidshunt-coil 9 and the impedance-coil 8, which areconnected to the service-mains 2 and 3 by means of the wires of and 7,or by a longitudinal adjustment of the said core within the shunt-coilby the described means or other proper manner. Obviously if theinductance of the said impedancecoil causes a lag of the current throughthecoil 9 of,say,

eighty degrees the presence of thesaid-lagging core 10 prevents themagnetism of said coil from being in phase with its current, and

with them'agnetisnnof the series coil 5 when 7 the translating devicesare no n-inductive. To

by means of the reluctance and'hysteresis of said core the progress ofsaid magnetismis further retarded-'say tendegrees-behihd the current'insaid shnnt-coihthereby securing the desired lag of said magnetismninetydegrees behind the line electromotive force. By

a combination or cooperation of thislagging shunt-field magnetism withthe magnetism of the series coil ashifting magnetic field is-producedadapted to actuate the said revoluble armature with a torqueproportional to the real watts. The retarding device, consisting of amagnet 17, a metallic disk 13, and the metal keeper 18,-is adapted tomake thespeed of said armature proportional to the energy consumed in awell-understood manner.

I do not wish to be understood as limiting myself to the use of asolidtool-steel core, as I have also obtained good results with othersolid magnetic mediums, such as other grades of steel, wrought andcastiron, and cast-steel. Neither do I confine myself to the theoriesherein expressed respecting the magnetic acing in inductive relationtherewith, a pressure-winding also in inductive relation to saidarmature, and an unlaminated magnetizable core for said pressure-windingfor maintaining the magnetism due to the pressure-winding in quadraturewith the pressure, substantially as described.

3. In a multifrequency induction motormeter, the combination withcurrent and pressure energizing windings, of an armature in inductiverelation therewith, and an unlaminated magnetizable core for saidpressurewinding for varying the magnetism due to the said coil tocompensate for variation of frequency, substantially as described.

4. In a multifrequency induction motormeter, the combination withcurrent and pressure energizing windings, of an armature in the form ofa revolnble disk in inductive relation therewith, and an unlaminatedmagnetizable core for said pressure-winding for varying the magnetismdue to the said coil to compensate for variation of frequency,substantially as described.

5. In a multifrequency induction motormeter, the combination withcurrent and pressure energizing windings, of an armature in inductiverelation therewith, and an unlaminated magnetizable core for saidpressurewinding for varying the magnetism due to the said coil tocompensate for variation of frequency, the pressure-winding and saidunlaminated core being located upon the same side of the armature,substantially as described.

6. In a multifrequency induction motormeter, the combination withcurrent and pressure energizing windings, of an armature in inductiverelation therewith, an unlaminated magnetizable core for saidpressure-winding for varying the magnetism due to the said coil tocompensate for variation of frequency, and an impedance-coil in circuitwith the pressure- Winding, substantially as described.

7. In an induction motor-meter, the combination with a revolublearmature, of a current-winding in inductive relation therewith, apressure-winding also in inductive relation to said armature, anunlaminated magnetizable core for said pressure-Winding for maintainingthe magnetism due to the pressurewinding in quadrature with thepressure, and an impedance-coil in series with the pressurewinding,substantially as described.

8. In a multifrequency induction motormeter, the combination withenergizing-windings receiving current from the generator, of an armaturein inductive relation therewith, and an unlaminated adjustable core incooperative relation with one of the said energizing-windings forvarying the magnetism due to the said coil to compensate for variationof frequency, substantially as described.

9. In an induction-meter, the combination with a movable armature, of acurrent-wind ing in inductive relation therewith,a pressure-winding alsoin inductive relation to the said armature, and an unlaminatedmagnetizable core for said pressure-winding for securing the requisitephase adjustment of the magnetism due to the pressure-winding,substantially as described.

10. In a multifrequency induction motormeter, the combination withcurrent and pressure energizing windings, of an armature in inductiverelation therewith, and an adjustable nnlaminated magnetizable core forsaid pressure-winding for varying the magnetism due to the said coil tocompensate for variation of frequency, substantially as described.

11. In an induction-meter, the combination with a movable armature, ofacurrent-winding, a pressure-winding in inductive relation to the saidarmature, and an unlaminated .magnetizable core for saidpressure-winding for securing the requisite phase adjustment ofthemagnetism due to thepressure-winding,

substantially as described.

12. In an induction-motor, the combination with a movable armature of awinding, a pressure-winding in inductive relation to the said armature,and an unlaminated magnetizable core for said pressure-winding forsecuring the requisite phase adjustment of the magnetism due to thepressure-winding, substantially as described.

13. In a multifrequency induction motormeter, the combination withcurrent and pressure energizing windings, of an armature in inductiverelation therewith, and an unlaminated magnetizable steel core for saidpressure-winding for varying the magnetism due to the said coil tocompensate for variation of frequency, substantially as described.

Signed by me at Fort Wayne, Allen county, State of Indiana, this 27thday of June, A. D. 1898.

THOMAS DUNCAN.

Witnesses:

EDWARD T. TIERNEY, MAUDE MERILLAT.

